1. Field of the Invention
The present invention relates to an electrode assembly, a cathode device and a plating apparatus that may be employed in an ideal manner when plating substrates for various types of electronic components, IC wafers or the like.
2. Discussion of the Background
During the plating process of substrates for various types of electronic components, IC wafers or the like, plating must be implemented within a limited planar area on the object that is to be plated, i. e., the substrate or the wafer. During such a process, plating is performed by placing a cathode device in surface contact with the surface of the object to be plated so that the cathode device encloses the area to be plated. Publications that disclose this prior art technology include Japanese Unexamined Patent Publication No. 66698/1992 and Japanese Unexamined Patent Publication No. 125596/1993. In the cathode devices of the known art disclosed in these publications, a cathode or an auxiliary electrode is placed in surface contact with the object to be plated.
Since this type of cathode device is employed to plate an object to be plated that is constituted of a substrate for an electronic component, an IC wafer or the like, it is crucial that the film thickness distribution be improved by achieving consistency in the plating film thickness at the object to be plated over the entire plate forming surface as a means for forming an element having consistent characteristics within the object to be plated.
However, there is still room for improvement in the consistency of the plating film thickness and the film thickness distribution in the prior art technologies including the technology mentioned above.